Residential gateways are widely used to connect devices in the home to the Internet or any other wide area network (WAN). Residential gateways use in particular digital subscriber line (DSL) technology that enables a high data rate transmission over copper lines or optical lines. During the years, several DSL standards have been established differing in data rates and in range, for example ADSL and VDSL, which are referred to in this context as xDSL. Also optical transmission for Internet services is well known, for example fiber-to-the-home (FTTH) and fiber-to-the premises (FTTP). Residential gateways, but also other devices such as routers, switches, telephones and set-top boxes, are understood in this context as customer premises equipment (CPE) devices.
Residential gateways including wireless technology have a key role in today's home and professional environments. A mechanism for connecting wireless devices to a local area network (LAN) is called Wi-Fi, which is a brand name of the Wi-Fi Alliance for devices using the IEEE 802.11 family of standards for wireless data transmission. The IEEE 802.11 standards define two types of wireless nodes, a general wireless device that can connect to other devices called a station (denoted as STA) and a special type of a STA that is in control of the network, namely an access point (denoted AP). A Wi-Fi network, often called a WLAN (wireless local area network), consists of an AP with one or several STA connected to the AP.
Due to its flexible and “invisible” nature, a lot of LAN applications are utilizing Wi-Fi rather than the classical wired Ethernet approach. This widespread usage of wireless LAN has exposed however a serious downside of using a shared medium technology: interference. Interference, both Wi-Fi and non-Wi-Fi related, leads to a degraded user experience due to the nature of 802.11. In its most common form, IEEE 802.11 networks apply a medium access method in which collisions are avoided by sensing that the medium is used (denoted as CSMA-CA). The medium access method is also commonly known as “listen before talk”, describing the essence of the method. Interference from any nature can hence block the medium and force all nodes to remain silent.
Therefore, in certain circumstances, the Wi-Fi connection can suffer from poor performance and even connection loss. Some of these circumstances are obvious and easy to explain to an end user. For example, if the distance between the station and the access point is too large, then signal levels are low and performance will degrade. Other circumstances are “invisible” and not understood by the end-user, e.g. a hidden node. A hidden node is invisible to some of the nodes of a network, leading to a practical failure of the CSMA-CA method which can cause packet collision/corruption over air. In many cases, the end-user is not able to diagnose the problem source and correct the issue.
In-home Wi-Fi network connectivity is correspondingly one of the main Internet service provider support costs and causes for help-desk calls. Today's focus for operators is mainly on Wi-Fi network install, associating a station with an access point. Internet service providers are therefore searching for ways to get a better understanding of the end-user's wireless environment including link quality and performance. Related to Wi-Fi performance, operators can use a remote management protocol such as Broadband Forum (noted BBF) TR-069 protocol, which provides access to Wi-Fi parameters as defined in the Internet Gateway Device data model BBF TR-181. But the information available via TR-069 is very limited and focused on data traffic. In some cases, an end-user is faced with an issue preventing Wi-Fi connection at all, correspondingly rendering TR-069 monitoring useless. Hence, when an end-user calls a help-desk, it can be a lengthy and expensive process to describe the home topology and diagnose the issue at hand.
The ideal way to analyze Wi-Fi issues, e.g. connection setup, interference, throughput, . . . , is by looking into the master node of the wireless LAN, namely the AP. The AP, as defined in IEEE 802.11, controls the network, hence all data and network control must be visible by the AP. The AP today can deliver statistics regarding packet transmission and signal levels, but only if a link between the AP and a STA can be established. The real issue why a link is dropped or why throughput is low, remains hidden to the internals of the AP. Full packet inspection is not possible, hence leaving technology or protocol analyzers in the dark when it comes down to pinpointing the real issues in a wireless LAN. Today, at best an AP can deliver statistics but no view on what is actually happening in the network.
What a person analyzing a Wi-Fi network is really interested in, is the full packet exchange between the AP and its client STAs, including the 802.11 management and control packets. On Ethernet, this method of packet capture exists and is fairly trivial. Ethernet cards can be put in “promiscuous mode”: this mode actually allows direct and transparent access to the send/receive queues of the Ethernet hardware to a third party software (e.g. Wireshark) that can then analyze the packet stream. The software does however not visualize the low level Ethernet traffic but only the traffic above the physical layer. For Ethernet, this level of analysis is sufficient as the physical medium itself is stable. Nevertheless, even on Ethernet one needs “more information”, if the link speed negotiation or duplex detection fails. On wireless networks, the multitude of such issues is enormously larger, hence the need to specifically look at the lower layer protocol exchanges in order to understand why the reported impact on the data link is present.
U.S. Pat. No. 8,102,866 discloses a centralized system for the monitoring of remote multimedia signals which monitors and assesses the quality of services distributed over an IP packet telecommunications network comprising a plurality of customer premises equipment, one of the items of such equipment being connectable to an access gateway, such as a digital subscriber line access multiplexer, via a line susceptible of receiving multimedia content such as data, voice and video over IP; the said content being returned directly to the access multiplexer via a return line.
U.S. Pat. No. 7,573, 859 discloses a system and method for remote monitoring in a wireless network using a remote probe. An access point links a wireless client to a wireless switch. The remote probe captures wireless packets, appends radio information, and forwards packets to a remote observer for analysis. In an embodiment, the observer may provide a protocol-level debug.